1. Field of the Invention
The present invention is related to a heat dissipation device with coarse surface capable of intensifying heat transfer and particularly to a heat dissipation device capable of promoting efficiency of heat transfer.
2. Brief Description of the Related Art
Due to precision of the electronic components being fabricated more precise than before, much more heat is generated by the electronic components accordingly. As a result, it is considerably insufficient to dissipate the heat to the ambient environment with the conventional natural or forced convection. Mostly, the current way to dissipate the heat is in that the heat sink is provided at the heat source side to guide the heat out. The cooling fins of the heat sink transmit the heat to the ambient environment naturally or forcedly.
However, there are some problems are still unable to be overcome while the popularly employed heat sink with a fan is in operation. For instance, temperature difference between the surfaces of the cooling fins and the airflow passing through the heat sink is merely 5-10° C. and it results in inadequate temperature gradient, and material and structure of the heat sink cause thermal resistance. The preceding problems lead to the conventional heat sink being incapable of dissipating larger amount of heat and the electronic components malfunctioning arose from heat dissipation.
Taiwan Utility Model Application No. 90220898, entitled “HEAT EXCHANGE FIN CAPABLE OF CREATING EDDY FLOW”, discloses a fin with several recesses and projections at the surface thereof and two or more pieces of the fins are combined to allow the projections on two adjacent fins contacting with each other. While the fins are assembled as a single unit, work fluid flows through the assembled fins along one-dimensional direction or two-dimensional directions. In this way, the work fluid not only passes through passages between resistant members formed with the recesses and projections but also hits the resistant members and changes both moving direction and moving speed thereof. Under this circumference, phenomenon of turbulence created by the work fluid is intensified to increase thermal convection effect between the work fluid and the respective fin.
However, the preceding prior art still has problems while in practice. The flow passage is reduced because of the resistant members between the fins and a great deal of reversed pressure is created to lessen fluid input. Next, frictional resistance is formed between the work fluid and the surface of the respective fin and between the work fluid and the resistant members, that is, there are two-dimensional fluid frictional resistant forces retarding the fluid speed. Further, thickness of boundary layer increases along with flow distance and, under this circumference, the thermal resistance increases accordingly to influence effect of heat transfer. Thus, heat is incapable of being carried out effectively.